The invention relates to friction plate clutches and it is concerned more particularly with vibration and wear problems which are incurred in certain types of these clutches when they are used on internal combustion engines.
A friction plate clutch of the type which is apt to be adversely affected by engine vibrations is shown for instance in U.S. Pat. No. 3,072,235 granted Jan. 8, 1963 to G. R. Aschauer. Loosely interfitted parts of said clutch comprise a hub of an axially fixed backplate, an axially reciprocable pressure plate splined on the hub, a rotatable adjusting ring having internal screw threads engaging external screw threads of the hub, an axially reciprocable shift collar and its supporting shaft; and elements of an articulated loading mechanism for the pressure plate.
In the engaged condition of the clutch, its loosely interfitted parts are loaded and thereby kept in fixed predetermined positions relative to each other regardless of vibrations transmitted to them from an engine. On the other hand, disengagement of the clutch unloads the loosely interfitted clutch parts and they will then be moved slightly but continuously relative to each other by vibrations transmitted to them from the engine.
When the clutch is kept disengaged for long periods of time while the engine is running, as in a tractor power take-off mechanism, the continuous relative movements of the loosely interfitted clutch parts cause objectionable wear of their mutual contact areas by a combination of sliding and impact. Such wear is aggravated in engine front end locations of the clutch because the erratic motion of the engine front end causes acceleration in all directions which in turn promote relative motion of the loosely interfitted and unloaded clutch parts.